Probable Tethyan control of Atlantic rifting with implications for Mediterranean tectonics

Abstract

New analysis of the paleogeographic constraints on the Mesozoic breakup of Pangaea have demonstrated links between the evolution of Paleo-Tethys and Tethys trenches and sea-floor spreading in the central Atlantic. Identified links include: (1) a common orientation for the mid-Atlantic spreading centre and the Paleo-Tethys and Tethys trenches parallel to tectonic longitudes of the governing relative plate motions (Fig. 1), (2) a common tectonic latitude for the poleward limits of the mid-Atlantic spreading centre in southern Newfoundland, Canada, and the Paleo-Tethys and Tethys trenches in western Europe (Fig. 1), and (3) sensitivity of mid-Atlantic rift kinematics to the diachronous collision of Cimmeria with southern Eurasia. These links are inferred to indicate the propagation of tectonic stresses from the Tethyan domain into the Atlantic domain and the driving influence of Tethyan subduction on the breakup of Pangaea. The balance between Tethyan closure and Atlantic opening carries fundamental implications for interpretations of Mediterranean tectonics as well. Deformation within the Mediterranean region is required to have been compatible with the Atlantic-Tethyan compensation. Candidate possibilities include a sinistral transform along northern Africa, local extension and convergent balance within the Alpine Mediterranean, a dextral transform through central Eurasia, or some combination thereof (Fig. 1). A review of the literature reveals only rare considerations of these necessary possibilities and a preference for incompatible models – in which spreading centres in both the Atlantic and Tethyan domains were inferred to have become connected due to propagating or offset rift segments – instead. Fundamental improvements to tectonic reconstructions of the Mesozoic Mediterranean appear likely now that the bounding Atlantic-Tethyan compensation relationship has been made explicit. (Go to www.searchanddiscovery.com to see figures.)

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015